Process of acylating carbohydrates



-paata 5a 25,1928:

- I-Tao:,s Ta-s f aaza:

own-r Ca-m aims n. mnm,nro1w, or renLmLNnw JERSEY, assienon mo :a. 1., DU POINT Dnmounsa COMPANY, or WILMINGTON, DELAWARE, a coaroaarxon errata,

' ms Drawing.

' d This invention relates to the acylation of a carbohydrate such, for. example, as cellu-' lose, starch,- dextrin, inulin,.etc., by treating the carbohydrate with a .ketene (that is, a

I}, carboalkylidena 3 and comprises. more particularly'the acetylation'of a carbo'-,

The acylated carbohydrate of most com-'- mercial importance at the-present timebe- 'rnocnss or acrnn'rnte cmomna'rns.

Application filed June 3, i925. ser al m: 34,783.

predict may be and usfially isthe chloro form soluble variety, butflin such case the acetone-soluble type may be readily" 'pre 40 pared by p ial hydrolysis of the cellulose.

acetate acco ding to known methods.

In place of sulphuric acid in theaabove process,- various other substances may be used as catalysts, such as hydrochloric acid,- 45

"phosphorus trichloride, etc.

gThe cellulose .-us'ed in. the above exam 1e nia be either a-modifiedor -an unmodi ed ce ulose.

5 Where the product to' be acetylated is to ing cellulose acetate, I shall describe'my instarch, the latter is suspended in glacial 7 vention more particularly in reference thereto, but itwill'be understood that the invention is .alsocapplicableto the producf tion of. esters of carbohydrates other than Qacid, until the formation of starch acetate cellulose, and of esters of other org'anicacids 0 of-greater molecular Weiht than acetic acid, j My invention, as app 'ed to-the produca little sulphuric acid (about one to 'five er cent of the weight of the cellulose used).

grade'tissue paper-of the acetic-acid, for, instance, and'ketene' assed through the suspension, preferably in the presence of a small percentage of sulphuric has progressed to the desired extent.

Iyclaim: 1. The process'of acetylat ing acarbohydrate'which comprises bringing'kete'ne into contact with said carbohydrate suspended 60 asuitable-liquidmedium.

'2. The process of acetylatin'g cellulose which comprises bringing ketene into contact with cellulose suspended in a suitable liquid-medium. I

v 3. The, process which com rises keteneinto a suspension of .-ce ulose in glacial acetic acid containin a small per cent,-

(larbo-methene, which is 'a gas,, is then passed based on the W611 ht of ce ulose, of a strong.

-through.'the siispermionuntil the cellulose has been converted 'into cellulose acetate and has, dissolved in the'glaci'al acetic acid; The,

resulting solution is then drowned in water w'f rec pitate celluloseacetate. I The v mineral acid, an then recovering the cellu-yflfl' 

